FileHelpers and CSV: what to do when a record can expand unbounded, horizontally

问题

I'm trying to parse this type of CSV file with FileHelpers:

Tom,1,2,3,4,5,6,7,8,9,10
Steve,1,2,3
Bob,1,2,3,4,5,6
Cthulhu,1,2,3,4,5
Greg,1,2,3,4,5,6,7,8,9,10,11,12,13,14

I can't figure out how to parse this with FileHelpers. I would imagine I should be able to do something like this:

[DelimitedRecord(",")]
public class MyRecord
{
    public string Name;

    public List<int> Values;
}

But that doesn't appear to be possible with FileHelpers. The best I can seem to do is this:

[DelimitedRecord(",")]
public class MyRecord
{
    public string Name;

    public string Values;

    public string[] ActualValuesInNiceArray
    {
        get { return Values.Split(new[] {','}, StringSplitOptions.RemoveEmptyEntries); }
    }
}

I then would need to split Values on commas to get the set of values for each record. Doesn't seem to be much of a point in using FileHelpers if I have to manually parse a portion of each record.

Am I missing something? I've gone over docs/examples, but can't seem to find a solution for my format. Excel has no trouble with my format, so I would imagine there is a way to do it with an existing free library (FileHelpers or some other library). Any ideas?

回答1:

You can use an Array Field and the library will do the work:

[DelimitedRecord(",")]
public class MyRecord
{
    public string Name;

    public int[] Values;
}

You can even use [FieldArrayLength(2, 8)]

[DelimitedRecord(",")]
public class MyRecord
{
    public string Name;

    [FieldArrayLength(2, 8)]
    public int[] Values;
}

The set the min/max number of values

I strongly recomend to download the last version of the library from here:

http://teamcity.codebetter.com/viewType.html?buildTypeId=bt65&tab=buildTypeStatusDiv

Check the artifacts section

回答2:

You could create a class MyRecord that holds all the potential values, e.g.

[DelimitedRecord(",")]
public class MyRecord
{
    public string Name;
    public int Value1;
    .....
    [FieldOptional]
    public int Value5;
    ......
    [FieldOptional]
    [FieldNullValue(typeof(int), "-1" )]
    public int Value14;
}

and make most of those fields optional (no. 5 through 14 in my example) and combine that with e.g. a FieldNullValue to handle those non-existing fields (or make those optional fields a nullable int:

 public int? Value5

来源：https://stackoverflow.com/questions/2356419/filehelpers-and-csv-what-to-do-when-a-record-can-expand-unbounded-horizontally

标签

.net

csv

filehelpers